summaryrefslogtreecommitdiffstats
path: root/arch/arm
diff options
context:
space:
mode:
authorRussell King <rmk+kernel@arm.linux.org.uk>2011-01-23 12:09:36 +0000
committerRussell King <rmk+kernel@arm.linux.org.uk>2011-02-23 17:24:16 +0000
commit617912440bf20497d23d01ab58076998aced3f15 (patch)
tree69bc841621171decddfd96c060cfa404184fdd2e /arch/arm
parent1dbfa187dad57d3e17207328ec8bd2d90b4177d2 (diff)
ARM: irq migration: ensure migration is handled safely
Ensure appropriate locks are taken to ensure that IRQ migration off the current CPU is race-free. We may have a concurrent set_affinity via procfs running on another CPU in parallel with the IRQ migration, resulting in unpredictable results. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm')
-rw-r--r--arch/arm/kernel/irq.c50
1 files changed, 31 insertions, 19 deletions
diff --git a/arch/arm/kernel/irq.c b/arch/arm/kernel/irq.c
index 2f19aa5f339..3535d3793e6 100644
--- a/arch/arm/kernel/irq.c
+++ b/arch/arm/kernel/irq.c
@@ -179,14 +179,21 @@ int __init arch_probe_nr_irqs(void)
#ifdef CONFIG_HOTPLUG_CPU
-static void route_irq(struct irq_desc *desc, unsigned int irq, unsigned int cpu)
+static bool migrate_one_irq(struct irq_data *d)
{
- pr_debug("IRQ%u: moving from cpu%u to cpu%u\n", irq, desc->irq_data.node, cpu);
+ unsigned int cpu = cpumask_any_and(d->affinity, cpu_online_mask);
+ bool ret = false;
- raw_spin_lock_irq(&desc->lock);
- desc->irq_data.chip->irq_set_affinity(&desc->irq_data,
- cpumask_of(cpu), true);
- raw_spin_unlock_irq(&desc->lock);
+ if (cpu >= nr_cpu_ids) {
+ cpu = cpumask_any(cpu_online_mask);
+ ret = true;
+ }
+
+ pr_debug("IRQ%u: moving from cpu%u to cpu%u\n", d->irq, d->node, cpu);
+
+ d->chip->irq_set_affinity(d, cpumask_of(cpu), true);
+
+ return ret;
}
/*
@@ -198,25 +205,30 @@ void migrate_irqs(void)
{
unsigned int i, cpu = smp_processor_id();
struct irq_desc *desc;
+ unsigned long flags;
+
+ local_irq_save(flags);
for_each_irq_desc(i, desc) {
struct irq_data *d = &desc->irq_data;
+ bool affinity_broken = false;
- if (d->node == cpu) {
- unsigned int newcpu = cpumask_any_and(d->affinity,
- cpu_online_mask);
- if (newcpu >= nr_cpu_ids) {
- if (printk_ratelimit())
- printk(KERN_INFO "IRQ%u no longer affine to CPU%u\n",
- i, cpu);
+ raw_spin_lock(&desc->lock);
+ do {
+ if (desc->action == NULL)
+ break;
- cpumask_setall(d->affinity);
- newcpu = cpumask_any_and(d->affinity,
- cpu_online_mask);
- }
+ if (d->node != cpu)
+ break;
- route_irq(desc, i, newcpu);
- }
+ affinity_broken = migrate_one_irq(d);
+ } while (0);
+ raw_spin_unlock(&desc->lock);
+
+ if (affinity_broken && printk_ratelimit())
+ pr_warning("IRQ%u no longer affine to CPU%u\n", i, cpu);
}
+
+ local_irq_restore(flags);
}
#endif /* CONFIG_HOTPLUG_CPU */